John VanSickle nous illumina en ce 2008-09-13 23:53 -->
> Severi Salminen wrote:
>>> * Instead of shooting RGB rays, shoot photons of a particular wave
>>> length, selected randomly from the spectrum of the light source at the
>>> emission point;
>>
>> Yes. This should be implemented at some point to enable accurate 
>> dispersion.
> 
> I should say that the weakness of this approach is that a surface that 
> is supposed to be a uniform color will now appear to be a mixture of 
> pixels that average to that color.
> 
>>> * A photon isn't drawn on the screen unless it hits the virtual film.
>>> Then you calculate its RGB value, and add that to the pixel at that
>>> point in the screen.
>>
>> I start the rays from film plane so all rays always hit the film. I'm 
>> not sure
>> if anyone does it the other way and how it works in practice.
> 
> So it traces from 'film' to light source, instead of the other way 
> around?  I had assumed that it went the other way.  Maybe I could try 
> writing a renderer that does that.
> 
> Regards,
> John
> 
> 
All ray tracers go from the camera to the objects in the scene then to the light 
source(s). It's called backward ray tracing. Much more effecient that way.

-- 
Alain
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If That Phone Was Up Your Butt, Maybe You Could Drive A Little Better!

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